The opening of an aircraft door can generally be broken down into several phases that succeed each other: unlocking and releasing the safety catch, lifting, pivoting and disengaging the door along the external side of the aircraft fuselage. In particular, triggering the lifting phase can enable the ice that may be present on the external side of the fuselage to be broken before continuing with opening the door through the pivoting and disengaging phases. For closing, the phases take place in the reverse order and according to inverse kinematics.
In emergency situations, it is necessary to be able to trigger door opening in a single operation. Due to operability constraints on airline personnel, the opening or closing force on the door actuation handle must be limited in normal utilization conditions and in emergency conditions.
In particular, slight icing of the door (for example, of the order of 2.5 mm thickness of ice on the fuselage) already causes opening difficulties, which does not allow an emergency evacuation of passengers in the safety conditions required in the event of evacuation to be performed. Heavy icing of the door (for example, of more than 6 mm thickness of ice) makes it difficult to open the door, which necessitates the intervention of several operators and causes a delay in disembarking the passengers.
The doors are therefore advantageously equipped with electric motors that will act to guarantee their opening through an appropriate supply of power. These motors control actuators that guide the door according to pre-established kinematics, with a lifting phase to break the ice on the exterior of the fuselage.
An aircraft electric door is known from the patent document EP 0 465 785, whose opening and closing kinematics are implemented by a dozen electric motors. These motors are digitally controlled to perform different functioning phases in a coordinated manner: pivoting, closing and locking, as well as the reverse functions.
The patent document U.S. Pat. No. 5,163,639 furthermore describes an aircraft electric passenger door equipped with two electric motors for controlling the operations: a motor for controlling the rotation of the door and a motor for controlling the means of opening/closing the door.
The electric door of the patent document EP 1 090 834 is also equipped with two electric motors actuated by a control and management unit. This unit transmits control signals to a first motor to lock/unlock and to lift a door lifting and (un)locking arm, and to a second motor to pivot the door and bring it to its final open position.
In critical emergency exit situations—fire risk, unsecured landing, serious technical problem—the door must be capable of releasing itself automatically from the fuselage after having actuated the handle. This actuation is generally provided by a pneumatic jack linked with a gas supply.
These solutions present major drawbacks with regard to safety, especially in cases of emergency opening, and more generally, with regard to the kinematics sequence. These problems are related to the coordination complexity between the motors in performing the different door opening/closing phases, and also to the presence of a pneumatic jack with its gas supply for activation in the event of an emergency. Moreover, breaking the external ice is not the subject of any special treatment in the motorized solutions.